Merging upstream version 1.67.1+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

4 files changed, 819 insertions, 371 deletions

diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs
new file mode 100644
index 000000000..752b53fbc
--- /dev/null
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs
@@ -0,0 +1,52 @@
+use rustc_hir::def_id::DefId;
+use rustc_infer::infer::InferCtxt;
+use rustc_infer::traits::{Obligation, ObligationCause, TraitObligation};
+use rustc_span::DUMMY_SP;
+
+use crate::traits::ObligationCtxt;
+
+pub fn recompute_applicable_impls<'tcx>(
+    infcx: &InferCtxt<'tcx>,
+    obligation: &TraitObligation<'tcx>,
+) -> Vec<DefId> {
+    let tcx = infcx.tcx;
+    let param_env = obligation.param_env;
+    let dummy_cause = ObligationCause::dummy();
+    let impl_may_apply = |impl_def_id| {
+        let ocx = ObligationCtxt::new_in_snapshot(infcx);
+        let placeholder_obligation =
+            infcx.replace_bound_vars_with_placeholders(obligation.predicate);
+        let obligation_trait_ref =
+            ocx.normalize(&dummy_cause, param_env, placeholder_obligation.trait_ref);
+
+        let impl_substs = infcx.fresh_substs_for_item(DUMMY_SP, impl_def_id);
+        let impl_trait_ref = tcx.bound_impl_trait_ref(impl_def_id).unwrap().subst(tcx, impl_substs);
+        let impl_trait_ref = ocx.normalize(&ObligationCause::dummy(), param_env, impl_trait_ref);
+
+        if let Err(_) = ocx.eq(&dummy_cause, param_env, obligation_trait_ref, impl_trait_ref) {
+            return false;
+        }
+
+        let impl_predicates = tcx.predicates_of(impl_def_id).instantiate(tcx, impl_substs);
+        ocx.register_obligations(
+            impl_predicates
+                .predicates
+                .iter()
+                .map(|&predicate| Obligation::new(tcx, dummy_cause.clone(), param_env, predicate)),
+        );
+
+        ocx.select_where_possible().is_empty()
+    };
+
+    let mut impls = Vec::new();
+    tcx.for_each_relevant_impl(
+        obligation.predicate.def_id(),
+        obligation.predicate.skip_binder().trait_ref.self_ty(),
+        |impl_def_id| {
+            if infcx.probe(move |_snapshot| impl_may_apply(impl_def_id)) {
+                impls.push(impl_def_id)
+            }
+        },
+    );
+    impls
+}
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
index 1217d264a..dda7b2b2f 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
@@ -1,34 +1,40 @@
+mod ambiguity;
 pub mod on_unimplemented;
 pub mod suggestions;
 
 use super::{
-    FulfillmentContext, FulfillmentError, FulfillmentErrorCode, MismatchedProjectionTypes,
-    Obligation, ObligationCause, ObligationCauseCode, OnUnimplementedDirective,
-    OnUnimplementedNote, OutputTypeParameterMismatch, Overflow, PredicateObligation,
-    SelectionContext, SelectionError, TraitNotObjectSafe,
+    FulfillmentError, FulfillmentErrorCode, MismatchedProjectionTypes, Obligation, ObligationCause,
+    ObligationCauseCode, ObligationCtxt, OutputTypeParameterMismatch, Overflow,
+    PredicateObligation, SelectionContext, SelectionError, TraitNotObjectSafe,
 };
-
 use crate::infer::error_reporting::{TyCategory, TypeAnnotationNeeded as ErrorCode};
 use crate::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
-use crate::infer::{self, InferCtxt, TyCtxtInferExt};
-use rustc_data_structures::fx::FxHashMap;
+use crate::infer::{self, InferCtxt};
+use crate::traits::query::evaluate_obligation::InferCtxtExt as _;
+use crate::traits::query::normalize::QueryNormalizeExt as _;
+use crate::traits::specialize::to_pretty_impl_header;
+use crate::traits::NormalizeExt;
+use on_unimplemented::OnUnimplementedNote;
+use on_unimplemented::TypeErrCtxtExt as _;
+use rustc_data_structures::fx::{FxHashMap, FxIndexMap};
 use rustc_errors::{
     pluralize, struct_span_err, Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed,
     MultiSpan, Style,
 };
 use rustc_hir as hir;
+use rustc_hir::def::Namespace;
 use rustc_hir::def_id::DefId;
 use rustc_hir::intravisit::Visitor;
 use rustc_hir::GenericParam;
 use rustc_hir::Item;
 use rustc_hir::Node;
 use rustc_infer::infer::error_reporting::TypeErrCtxt;
-use rustc_infer::infer::TypeTrace;
-use rustc_infer::traits::TraitEngine;
+use rustc_infer::infer::{InferOk, TypeTrace};
 use rustc_middle::traits::select::OverflowError;
 use rustc_middle::ty::abstract_const::NotConstEvaluatable;
 use rustc_middle::ty::error::ExpectedFound;
 use rustc_middle::ty::fold::{TypeFolder, TypeSuperFoldable};
+use rustc_middle::ty::print::{FmtPrinter, Print};
 use rustc_middle::ty::{
     self, SubtypePredicate, ToPolyTraitRef, ToPredicate, TraitRef, Ty, TyCtxt, TypeFoldable,
     TypeVisitable,
@@ -40,11 +46,6 @@ use rustc_span::{ExpnKind, Span, DUMMY_SP};
 use std::fmt;
 use std::iter;
 use std::ops::ControlFlow;
-
-use crate::traits::query::evaluate_obligation::InferCtxtExt as _;
-use crate::traits::query::normalize::AtExt as _;
-use crate::traits::specialize::to_pretty_impl_header;
-use on_unimplemented::TypeErrCtxtExt as _;
 use suggestions::TypeErrCtxtExt as _;
 
 pub use rustc_infer::traits::error_reporting::*;
@@ -70,7 +71,7 @@ pub trait InferCtxtExt<'tcx> {
     /// returns a span and `ArgKind` information that describes the
     /// arguments it expects. This can be supplied to
     /// `report_arg_count_mismatch`.
-    fn get_fn_like_arguments(&self, node: Node<'_>) -> Option<(Span, Vec<ArgKind>)>;
+    fn get_fn_like_arguments(&self, node: Node<'_>) -> Option<(Span, Option<Span>, Vec<ArgKind>)>;
 
     /// Reports an error when the number of arguments needed by a
     /// trait match doesn't match the number that the expression
@@ -82,6 +83,7 @@ pub trait InferCtxtExt<'tcx> {
         expected_args: Vec<ArgKind>,
         found_args: Vec<ArgKind>,
         is_closure: bool,
+        closure_pipe_span: Option<Span>,
     ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>;
 
     /// Checks if the type implements one of `Fn`, `FnMut`, or `FnOnce`
@@ -97,24 +99,36 @@ pub trait InferCtxtExt<'tcx> {
 }
 
 pub trait TypeErrCtxtExt<'tcx> {
+    fn report_overflow_error<T>(
+        &self,
+        predicate: &T,
+        span: Span,
+        suggest_increasing_limit: bool,
+        mutate: impl FnOnce(&mut Diagnostic),
+    ) -> !
+    where
+        T: fmt::Display
+            + TypeFoldable<'tcx>
+            + Print<'tcx, FmtPrinter<'tcx, 'tcx>, Output = FmtPrinter<'tcx, 'tcx>>,
+        <T as Print<'tcx, FmtPrinter<'tcx, 'tcx>>>::Error: std::fmt::Debug;
+
     fn report_fulfillment_errors(
         &self,
         errors: &[FulfillmentError<'tcx>],
         body_id: Option<hir::BodyId>,
-        fallback_has_occurred: bool,
     ) -> ErrorGuaranteed;
 
-    fn report_overflow_error<T>(
+    fn report_overflow_obligation<T>(
         &self,
         obligation: &Obligation<'tcx, T>,
         suggest_increasing_limit: bool,
     ) -> !
     where
-        T: fmt::Display + TypeFoldable<'tcx>;
+        T: ToPredicate<'tcx> + Clone;
 
     fn suggest_new_overflow_limit(&self, err: &mut Diagnostic);
 
-    fn report_overflow_error_cycle(&self, cycle: &[PredicateObligation<'tcx>]) -> !;
+    fn report_overflow_obligation_cycle(&self, cycle: &[PredicateObligation<'tcx>]) -> !;
 
     /// The `root_obligation` parameter should be the `root_obligation` field
     /// from a `FulfillmentError`. If no `FulfillmentError` is available,
@@ -124,7 +138,6 @@ pub trait TypeErrCtxtExt<'tcx> {
         obligation: PredicateObligation<'tcx>,
         root_obligation: &PredicateObligation<'tcx>,
         error: &SelectionError<'tcx>,
-        fallback_has_occurred: bool,
     );
 }
 
@@ -133,15 +146,16 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
     /// returns a span and `ArgKind` information that describes the
     /// arguments it expects. This can be supplied to
     /// `report_arg_count_mismatch`.
-    fn get_fn_like_arguments(&self, node: Node<'_>) -> Option<(Span, Vec<ArgKind>)> {
+    fn get_fn_like_arguments(&self, node: Node<'_>) -> Option<(Span, Option<Span>, Vec<ArgKind>)> {
         let sm = self.tcx.sess.source_map();
         let hir = self.tcx.hir();
         Some(match node {
             Node::Expr(&hir::Expr {
-                kind: hir::ExprKind::Closure(&hir::Closure { body, fn_decl_span, .. }),
+                kind: hir::ExprKind::Closure(&hir::Closure { body, fn_decl_span, fn_arg_span, .. }),
                 ..
             }) => (
                 fn_decl_span,
+                fn_arg_span,
                 hir.body(body)
                     .params
                     .iter()
@@ -172,6 +186,7 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
                 kind: hir::TraitItemKind::Fn(ref sig, _), ..
             }) => (
                 sig.span,
+                None,
                 sig.decl
                     .inputs
                     .iter()
@@ -186,7 +201,7 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
             ),
             Node::Ctor(ref variant_data) => {
                 let span = variant_data.ctor_hir_id().map_or(DUMMY_SP, |id| hir.span(id));
-                (span, vec![ArgKind::empty(); variant_data.fields().len()])
+                (span, None, vec![ArgKind::empty(); variant_data.fields().len()])
             }
             _ => panic!("non-FnLike node found: {:?}", node),
         })
@@ -202,6 +217,7 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
         expected_args: Vec<ArgKind>,
         found_args: Vec<ArgKind>,
         is_closure: bool,
+        closure_arg_span: Option<Span>,
     ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
         let kind = if is_closure { "closure" } else { "function" };
 
@@ -239,24 +255,13 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
         if let Some(found_span) = found_span {
             err.span_label(found_span, format!("takes {}", found_str));
 
-            // move |_| { ... }
-            // ^^^^^^^^-- def_span
-            //
-            // move |_| { ... }
-            // ^^^^^-- prefix
-            let prefix_span = self.tcx.sess.source_map().span_until_non_whitespace(found_span);
-            // move |_| { ... }
-            //      ^^^-- pipe_span
-            let pipe_span =
-                if let Some(span) = found_span.trim_start(prefix_span) { span } else { found_span };
-
             // Suggest to take and ignore the arguments with expected_args_length `_`s if
             // found arguments is empty (assume the user just wants to ignore args in this case).
             // For example, if `expected_args_length` is 2, suggest `|_, _|`.
             if found_args.is_empty() && is_closure {
                 let underscores = vec!["_"; expected_args.len()].join(", ");
                 err.span_suggestion_verbose(
-                    pipe_span,
+                    closure_arg_span.unwrap_or(found_span),
                     &format!(
                         "consider changing the closure to take and ignore the expected argument{}",
                         pluralize!(expected_args.len())
@@ -344,22 +349,19 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
                     span: DUMMY_SP,
                     kind: TypeVariableOriginKind::MiscVariable,
                 });
-                let substs = self.tcx.mk_substs_trait(ty.skip_binder(), &[var.into()]);
+                let trait_ref = self.tcx.mk_trait_ref(trait_def_id, [ty.skip_binder(), var]);
                 let obligation = Obligation::new(
+                    self.tcx,
                     ObligationCause::dummy(),
                     param_env,
-                    ty.rebind(ty::TraitPredicate {
-                        trait_ref: ty::TraitRef::new(trait_def_id, substs),
-                        constness,
-                        polarity,
-                    })
-                    .to_predicate(self.tcx),
+                    ty.rebind(ty::TraitPredicate { trait_ref, constness, polarity }),
                 );
-                let mut fulfill_cx = FulfillmentContext::new_in_snapshot();
-                fulfill_cx.register_predicate_obligation(self, obligation);
-                if fulfill_cx.select_all_or_error(self).is_empty() {
+                let ocx = ObligationCtxt::new_in_snapshot(self);
+                ocx.register_obligation(obligation);
+                if ocx.select_all_or_error().is_empty() {
                     return Ok((
-                        ty::ClosureKind::from_def_id(self.tcx, trait_def_id)
+                        self.tcx
+                            .fn_trait_kind_from_def_id(trait_def_id)
                             .expect("expected to map DefId to ClosureKind"),
                         ty.rebind(self.resolve_vars_if_possible(var)),
                     ));
@@ -375,7 +377,6 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         &self,
         errors: &[FulfillmentError<'tcx>],
         body_id: Option<hir::BodyId>,
-        fallback_has_occurred: bool,
     ) -> ErrorGuaranteed {
         #[derive(Debug)]
         struct ErrorDescriptor<'tcx> {
@@ -383,7 +384,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             index: Option<usize>, // None if this is an old error
         }
 
-        let mut error_map: FxHashMap<_, Vec<_>> = self
+        let mut error_map: FxIndexMap<_, Vec<_>> = self
             .reported_trait_errors
             .borrow()
             .iter()
@@ -452,7 +453,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
 
         for (error, suppressed) in iter::zip(errors, is_suppressed) {
             if !suppressed {
-                self.report_fulfillment_error(error, body_id, fallback_has_occurred);
+                self.report_fulfillment_error(error, body_id);
             }
         }
 
@@ -467,39 +468,84 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
     /// occurrences in any case.
     fn report_overflow_error<T>(
         &self,
-        obligation: &Obligation<'tcx, T>,
+        predicate: &T,
+        span: Span,
         suggest_increasing_limit: bool,
+        mutate: impl FnOnce(&mut Diagnostic),
     ) -> !
     where
-        T: fmt::Display + TypeFoldable<'tcx>,
+        T: fmt::Display
+            + TypeFoldable<'tcx>
+            + Print<'tcx, FmtPrinter<'tcx, 'tcx>, Output = FmtPrinter<'tcx, 'tcx>>,
+        <T as Print<'tcx, FmtPrinter<'tcx, 'tcx>>>::Error: std::fmt::Debug,
     {
-        let predicate = self.resolve_vars_if_possible(obligation.predicate.clone());
+        let predicate = self.resolve_vars_if_possible(predicate.clone());
+        let mut pred_str = predicate.to_string();
+
+        if pred_str.len() > 50 {
+            // We don't need to save the type to a file, we will be talking about this type already
+            // in a separate note when we explain the obligation, so it will be available that way.
+            pred_str = predicate
+                .print(FmtPrinter::new_with_limit(
+                    self.tcx,
+                    Namespace::TypeNS,
+                    rustc_session::Limit(6),
+                ))
+                .unwrap()
+                .into_buffer();
+        }
         let mut err = struct_span_err!(
             self.tcx.sess,
-            obligation.cause.span,
+            span,
             E0275,
             "overflow evaluating the requirement `{}`",
-            predicate
+            pred_str,
         );
 
         if suggest_increasing_limit {
             self.suggest_new_overflow_limit(&mut err);
         }
 
-        self.note_obligation_cause_code(
-            &mut err,
-            &obligation.predicate,
-            obligation.param_env,
-            obligation.cause.code(),
-            &mut vec![],
-            &mut Default::default(),
-        );
+        mutate(&mut err);
 
         err.emit();
         self.tcx.sess.abort_if_errors();
         bug!();
     }
 
+    /// Reports that an overflow has occurred and halts compilation. We
+    /// halt compilation unconditionally because it is important that
+    /// overflows never be masked -- they basically represent computations
+    /// whose result could not be truly determined and thus we can't say
+    /// if the program type checks or not -- and they are unusual
+    /// occurrences in any case.
+    fn report_overflow_obligation<T>(
+        &self,
+        obligation: &Obligation<'tcx, T>,
+        suggest_increasing_limit: bool,
+    ) -> !
+    where
+        T: ToPredicate<'tcx> + Clone,
+    {
+        let predicate = obligation.predicate.clone().to_predicate(self.tcx);
+        let predicate = self.resolve_vars_if_possible(predicate);
+        self.report_overflow_error(
+            &predicate,
+            obligation.cause.span,
+            suggest_increasing_limit,
+            |err| {
+                self.note_obligation_cause_code(
+                    err,
+                    &predicate,
+                    obligation.param_env,
+                    obligation.cause.code(),
+                    &mut vec![],
+                    &mut Default::default(),
+                );
+            },
+        );
+    }
+
     fn suggest_new_overflow_limit(&self, err: &mut Diagnostic) {
         let suggested_limit = match self.tcx.recursion_limit() {
             Limit(0) => Limit(2),
@@ -514,11 +560,11 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
     }
 
     /// Reports that a cycle was detected which led to overflow and halts
-    /// compilation. This is equivalent to `report_overflow_error` except
+    /// compilation. This is equivalent to `report_overflow_obligation` except
     /// that we can give a more helpful error message (and, in particular,
     /// we do not suggest increasing the overflow limit, which is not
     /// going to help).
-    fn report_overflow_error_cycle(&self, cycle: &[PredicateObligation<'tcx>]) -> ! {
+    fn report_overflow_obligation_cycle(&self, cycle: &[PredicateObligation<'tcx>]) -> ! {
         let cycle = self.resolve_vars_if_possible(cycle.to_owned());
         assert!(!cycle.is_empty());
 
@@ -526,7 +572,10 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
 
         // The 'deepest' obligation is most likely to have a useful
         // cause 'backtrace'
-        self.report_overflow_error(cycle.iter().max_by_key(|p| p.recursion_depth).unwrap(), false);
+        self.report_overflow_obligation(
+            cycle.iter().max_by_key(|p| p.recursion_depth).unwrap(),
+            false,
+        );
     }
 
     fn report_selection_error(
@@ -534,22 +583,15 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         mut obligation: PredicateObligation<'tcx>,
         root_obligation: &PredicateObligation<'tcx>,
         error: &SelectionError<'tcx>,
-        fallback_has_occurred: bool,
     ) {
-        self.set_tainted_by_errors();
         let tcx = self.tcx;
         let mut span = obligation.cause.span;
+        // FIXME: statically guarantee this by tainting after the diagnostic is emitted
+        self.set_tainted_by_errors(
+            tcx.sess.delay_span_bug(span, "`report_selection_error` did not emit an error"),
+        );
 
         let mut err = match *error {
-            SelectionError::Ambiguous(ref impls) => {
-                let mut err = self.tcx.sess.struct_span_err(
-                    obligation.cause.span,
-                    &format!("multiple applicable `impl`s for `{}`", obligation.predicate),
-                );
-                self.annotate_source_of_ambiguity(&mut err, impls, obligation.predicate);
-                err.emit();
-                return;
-            }
             SelectionError::Unimplemented => {
                 // If this obligation was generated as a result of well-formedness checking, see if we
                 // can get a better error message by performing HIR-based well-formedness checking.
@@ -582,7 +624,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
 
                 let bound_predicate = obligation.predicate.kind();
                 match bound_predicate.skip_binder() {
-                    ty::PredicateKind::Trait(trait_predicate) => {
+                    ty::PredicateKind::Clause(ty::Clause::Trait(trait_predicate)) => {
                         let trait_predicate = bound_predicate.rebind(trait_predicate);
                         let mut trait_predicate = self.resolve_vars_if_possible(trait_predicate);
 
@@ -663,40 +705,32 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                                 ))
                         );
 
-                        if is_try_conversion {
-                            let none_error = self
-                                .tcx
-                                .get_diagnostic_item(sym::none_error)
-                                .map(|def_id| tcx.type_of(def_id));
-                            let should_convert_option_to_result =
-                                Some(trait_ref.skip_binder().substs.type_at(1)) == none_error;
-                            let should_convert_result_to_option =
-                                Some(trait_ref.self_ty().skip_binder()) == none_error;
-                            if should_convert_option_to_result {
-                                err.span_suggestion_verbose(
-                                    span.shrink_to_lo(),
-                                    "consider converting the `Option<T>` into a `Result<T, _>` \
-                                     using `Option::ok_or` or `Option::ok_or_else`",
-                                    ".ok_or_else(|| /* error value */)",
-                                    Applicability::HasPlaceholders,
-                                );
-                            } else if should_convert_result_to_option {
-                                err.span_suggestion_verbose(
-                                    span.shrink_to_lo(),
-                                    "consider converting the `Result<T, _>` into an `Option<T>` \
-                                     using `Result::ok`",
-                                    ".ok()",
-                                    Applicability::MachineApplicable,
-                                );
-                            }
-                            if let Some(ret_span) = self.return_type_span(&obligation) {
-                                err.span_label(
-                                    ret_span,
-                                    &format!(
-                                        "expected `{}` because of this",
-                                        trait_ref.skip_binder().self_ty()
-                                    ),
-                                );
+                        if is_try_conversion && let Some(ret_span) = self.return_type_span(&obligation) {
+                            err.span_label(
+                                ret_span,
+                                &format!(
+                                    "expected `{}` because of this",
+                                    trait_ref.skip_binder().self_ty()
+                                ),
+                            );
+                        }
+
+                        if Some(trait_ref.def_id()) == tcx.lang_items().tuple_trait() {
+                            match obligation.cause.code().peel_derives() {
+                                ObligationCauseCode::RustCall => {
+                                    err.set_primary_message("functions with the \"rust-call\" ABI must take a single non-self tuple argument");
+                                }
+                                ObligationCauseCode::BindingObligation(def_id, _)
+                                | ObligationCauseCode::ItemObligation(def_id)
+                                    if tcx.is_fn_trait(*def_id) =>
+                                {
+                                    err.code(rustc_errors::error_code!(E0059));
+                                    err.set_primary_message(format!(
+                                        "type parameter to bare `{}` trait must be a tuple",
+                                        tcx.def_path_str(*def_id)
+                                    ));
+                                }
+                                _ => {}
                             }
                         }
 
@@ -848,12 +882,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                             );
                         }
 
-                        let is_fn_trait = [
-                            self.tcx.lang_items().fn_trait(),
-                            self.tcx.lang_items().fn_mut_trait(),
-                            self.tcx.lang_items().fn_once_trait(),
-                        ]
-                        .contains(&Some(trait_ref.def_id()));
+                        let is_fn_trait = tcx.is_fn_trait(trait_ref.def_id());
                         let is_target_feature_fn = if let ty::FnDef(def_id, _) =
                             *trait_ref.skip_binder().self_ty().kind()
                         {
@@ -883,7 +912,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                             // Note if the `FnMut` or `FnOnce` is less general than the trait we're trying
                             // to implement.
                             let selected_kind =
-                                ty::ClosureKind::from_def_id(self.tcx, trait_ref.def_id())
+                                self.tcx.fn_trait_kind_from_def_id(trait_ref.def_id())
                                     .expect("expected to map DefId to ClosureKind");
                             if !implemented_kind.extends(selected_kind) {
                                 err.note(
@@ -974,7 +1003,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                                 // useful for less general traits.
                                 if peeled
                                     && !self.tcx.trait_is_auto(def_id)
-                                    && !self.tcx.lang_items().items().contains(&Some(def_id))
+                                    && !self.tcx.lang_items().iter().any(|(_, id)| id == def_id)
                                 {
                                     let trait_ref = trait_pred.to_poly_trait_ref();
                                     let impl_candidates =
@@ -1000,16 +1029,12 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                         // variable that used to fallback to `()` now falling back to `!`. Issue a
                         // note informing about the change in behaviour.
                         if trait_predicate.skip_binder().self_ty().is_never()
-                            && fallback_has_occurred
+                            && self.fallback_has_occurred
                         {
-                            let predicate = trait_predicate.map_bound(|mut trait_pred| {
-                                trait_pred.trait_ref.substs = self.tcx.mk_substs_trait(
-                                    self.tcx.mk_unit(),
-                                    &trait_pred.trait_ref.substs[1..],
-                                );
-                                trait_pred
+                            let predicate = trait_predicate.map_bound(|trait_pred| {
+                                trait_pred.with_self_type(self.tcx, self.tcx.mk_unit())
                             });
-                            let unit_obligation = obligation.with(predicate.to_predicate(tcx));
+                            let unit_obligation = obligation.with(tcx, predicate);
                             if self.predicate_may_hold(&unit_obligation) {
                                 err.note(
                                     "this error might have been caused by changes to \
@@ -1062,9 +1087,9 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                         span_bug!(span, "coerce requirement gave wrong error: `{:?}`", predicate)
                     }
 
-                    ty::PredicateKind::RegionOutlives(..)
-                    | ty::PredicateKind::Projection(..)
-                    | ty::PredicateKind::TypeOutlives(..) => {
+                    ty::PredicateKind::Clause(ty::Clause::RegionOutlives(..))
+                    | ty::PredicateKind::Clause(ty::Clause::Projection(..))
+                    | ty::PredicateKind::Clause(ty::Clause::TypeOutlives(..)) => {
                         let predicate = self.resolve_vars_if_possible(obligation.predicate);
                         struct_span_err!(
                             self.tcx.sess,
@@ -1177,6 +1202,8 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                         )
                     }
 
+                    ty::PredicateKind::Ambiguous => span_bug!(span, "ambiguous"),
+
                     ty::PredicateKind::TypeWellFormedFromEnv(..) => span_bug!(
                         span,
                         "TypeWellFormedFromEnv predicate should only exist in the environment"
@@ -1260,13 +1287,14 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                         obligation.cause.code(),
                     )
                 } else {
-                    let (closure_span, found) = found_did
+                    let (closure_span, closure_arg_span, found) = found_did
                         .and_then(|did| {
                             let node = self.tcx.hir().get_if_local(did)?;
-                            let (found_span, found) = self.get_fn_like_arguments(node)?;
-                            Some((Some(found_span), found))
+                            let (found_span, closure_arg_span, found) =
+                                self.get_fn_like_arguments(node)?;
+                            Some((Some(found_span), closure_arg_span, found))
                         })
-                        .unwrap_or((found_span, found));
+                        .unwrap_or((found_span, None, found));
 
                     self.report_arg_count_mismatch(
                         span,
@@ -1274,6 +1302,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                         expected,
                         found,
                         found_trait_ty.is_closure(),
+                        closure_arg_span,
                     )
                 }
             }
@@ -1366,7 +1395,6 @@ trait InferCtxtPrivExt<'tcx> {
         &self,
         error: &FulfillmentError<'tcx>,
         body_id: Option<hir::BodyId>,
-        fallback_has_occurred: bool,
     );
 
     fn report_projection_error(
@@ -1483,9 +1511,10 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         // FIXME: It should be possible to deal with `ForAll` in a cleaner way.
         let bound_error = error.kind();
         let (cond, error) = match (cond.kind().skip_binder(), bound_error.skip_binder()) {
-            (ty::PredicateKind::Trait(..), ty::PredicateKind::Trait(error)) => {
-                (cond, bound_error.rebind(error))
-            }
+            (
+                ty::PredicateKind::Clause(ty::Clause::Trait(..)),
+                ty::PredicateKind::Clause(ty::Clause::Trait(error)),
+            ) => (cond, bound_error.rebind(error)),
             _ => {
                 // FIXME: make this work in other cases too.
                 return false;
@@ -1494,7 +1523,9 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
 
         for obligation in super::elaborate_predicates(self.tcx, std::iter::once(cond)) {
             let bound_predicate = obligation.predicate.kind();
-            if let ty::PredicateKind::Trait(implication) = bound_predicate.skip_binder() {
+            if let ty::PredicateKind::Clause(ty::Clause::Trait(implication)) =
+                bound_predicate.skip_binder()
+            {
                 let error = error.to_poly_trait_ref();
                 let implication = bound_predicate.rebind(implication.trait_ref);
                 // FIXME: I'm just not taking associated types at all here.
@@ -1516,7 +1547,6 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         &self,
         error: &FulfillmentError<'tcx>,
         body_id: Option<hir::BodyId>,
-        fallback_has_occurred: bool,
     ) {
         match error.code {
             FulfillmentErrorCode::CodeSelectionError(ref selection_error) => {
@@ -1524,7 +1554,6 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                     error.obligation.clone(),
                     &error.root_obligation,
                     selection_error,
-                    fallback_has_occurred,
                 );
             }
             FulfillmentErrorCode::CodeProjectionError(ref e) => {
@@ -1567,7 +1596,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 diag.emit();
             }
             FulfillmentErrorCode::CodeCycle(ref cycle) => {
-                self.report_overflow_error_cycle(cycle);
+                self.report_overflow_obligation_cycle(cycle);
             }
         }
     }
@@ -1585,29 +1614,26 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         }
 
         self.probe(|_| {
-            let mut err = error.err;
-            let mut values = None;
+            let ocx = ObligationCtxt::new_in_snapshot(self);
 
             // try to find the mismatched types to report the error with.
             //
             // this can fail if the problem was higher-ranked, in which
             // cause I have no idea for a good error message.
             let bound_predicate = predicate.kind();
-            if let ty::PredicateKind::Projection(data) = bound_predicate.skip_binder() {
-                let mut selcx = SelectionContext::new(self);
+            let (values, err) = if let ty::PredicateKind::Clause(ty::Clause::Projection(data)) =
+                bound_predicate.skip_binder()
+            {
                 let data = self.replace_bound_vars_with_fresh_vars(
                     obligation.cause.span,
                     infer::LateBoundRegionConversionTime::HigherRankedType,
                     bound_predicate.rebind(data),
                 );
-                let mut obligations = vec![];
-                let normalized_ty = super::normalize_projection_type(
-                    &mut selcx,
+                let normalized_ty = ocx.normalize(
+                    &obligation.cause,
                     obligation.param_env,
-                    data.projection_ty,
-                    obligation.cause.clone(),
-                    0,
-                    &mut obligations,
+                    self.tcx
+                        .mk_projection(data.projection_ty.item_def_id, data.projection_ty.substs),
                 );
 
                 debug!(?obligation.cause, ?obligation.param_env);
@@ -1623,25 +1649,40 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                         | ObligationCauseCode::ObjectCastObligation(..)
                         | ObligationCauseCode::OpaqueType
                 );
-                if let Err(new_err) = self.at(&obligation.cause, obligation.param_env).eq_exp(
+                let expected_ty = data.term.ty().unwrap_or_else(|| self.tcx.ty_error());
+
+                // constrain inference variables a bit more to nested obligations from normalize so
+                // we can have more helpful errors.
+                ocx.select_where_possible();
+
+                if let Err(new_err) = ocx.eq_exp(
+                    &obligation.cause,
+                    obligation.param_env,
                     is_normalized_ty_expected,
                     normalized_ty,
-                    data.term,
+                    expected_ty,
                 ) {
-                    values = Some((data, is_normalized_ty_expected, normalized_ty, data.term));
-                    err = new_err;
+                    (Some((data, is_normalized_ty_expected, normalized_ty, expected_ty)), new_err)
+                } else {
+                    (None, error.err)
                 }
-            }
+            } else {
+                (None, error.err)
+            };
 
             let msg = values
                 .and_then(|(predicate, _, normalized_ty, expected_ty)| {
-                    self.maybe_detailed_projection_msg(predicate, normalized_ty, expected_ty)
+                    self.maybe_detailed_projection_msg(
+                        predicate,
+                        normalized_ty.into(),
+                        expected_ty.into(),
+                    )
                 })
                 .unwrap_or_else(|| format!("type mismatch resolving `{}`", predicate));
             let mut diag = struct_span_err!(self.tcx.sess, obligation.cause.span, E0271, "{msg}");
 
             let secondary_span = match predicate.kind().skip_binder() {
-                ty::PredicateKind::Projection(proj) => self
+                ty::PredicateKind::Clause(ty::Clause::Projection(proj)) => self
                     .tcx
                     .opt_associated_item(proj.projection_ty.item_def_id)
                     .and_then(|trait_assoc_item| {
@@ -1677,11 +1718,11 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 &mut diag,
                 &obligation.cause,
                 secondary_span,
-                values.map(|(_, is_normalized_ty_expected, normalized_ty, term)| {
+                values.map(|(_, is_normalized_ty_expected, normalized_ty, expected_ty)| {
                     infer::ValuePairs::Terms(ExpectedFound::new(
                         is_normalized_ty_expected,
-                        normalized_ty,
-                        term,
+                        normalized_ty.into(),
+                        expected_ty.into(),
                     ))
                 }),
                 err,
@@ -1733,7 +1774,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 ty::Bool => Some(0),
                 ty::Char => Some(1),
                 ty::Str => Some(2),
-                ty::Adt(def, _) if tcx.is_diagnostic_item(sym::String, def.did()) => Some(2),
+                ty::Adt(def, _) if Some(def.did()) == tcx.lang_items().string() => Some(2),
                 ty::Int(..)
                 | ty::Uint(..)
                 | ty::Float(..)
@@ -1811,7 +1852,8 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         &self,
         trait_pred: ty::PolyTraitPredicate<'tcx>,
     ) -> Vec<ImplCandidate<'tcx>> {
-        self.tcx
+        let mut candidates: Vec<_> = self
+            .tcx
             .all_impls(trait_pred.def_id())
             .filter_map(|def_id| {
                 if self.tcx.impl_polarity(def_id) == ty::ImplPolarity::Negative
@@ -1827,7 +1869,14 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 self.fuzzy_match_tys(trait_pred.skip_binder().self_ty(), imp.self_ty(), false)
                     .map(|similarity| ImplCandidate { trait_ref: imp, similarity })
             })
-            .collect()
+            .collect();
+        if candidates.iter().any(|c| matches!(c.similarity, CandidateSimilarity::Exact { .. })) {
+            // If any of the candidates is a perfect match, we don't want to show all of them.
+            // This is particularly relevant for the case of numeric types (as they all have the
+            // same cathegory).
+            candidates.retain(|c| matches!(c.similarity, CandidateSimilarity::Exact { .. }));
+        }
+        candidates
     }
 
     fn report_similar_impl_candidates(
@@ -1898,7 +1947,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         let def_id = trait_ref.def_id();
         if impl_candidates.is_empty() {
             if self.tcx.trait_is_auto(def_id)
-                || self.tcx.lang_items().items().contains(&Some(def_id))
+                || self.tcx.lang_items().iter().any(|(_, id)| id == def_id)
                 || self.tcx.get_diagnostic_name(def_id).is_some()
             {
                 // Mentioning implementers of `Copy`, `Debug` and friends is not useful.
@@ -1935,14 +1984,6 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             return report(normalized_impl_candidates, err);
         }
 
-        let normalize = |candidate| {
-            let infcx = self.tcx.infer_ctxt().build();
-            infcx
-                .at(&ObligationCause::dummy(), ty::ParamEnv::empty())
-                .normalize(candidate)
-                .map_or(candidate, |normalized| normalized.value)
-        };
-
         // Sort impl candidates so that ordering is consistent for UI tests.
         // because the ordering of `impl_candidates` may not be deterministic:
         // https://github.com/rust-lang/rust/pull/57475#issuecomment-455519507
@@ -1952,7 +1993,11 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         let mut normalized_impl_candidates_and_similarities = impl_candidates
             .into_iter()
             .map(|ImplCandidate { trait_ref, similarity }| {
-                let normalized = normalize(trait_ref);
+                // FIXME(compiler-errors): This should be using `NormalizeExt::normalize`
+                let normalized = self
+                    .at(&ObligationCause::dummy(), ty::ParamEnv::empty())
+                    .query_normalize(trait_ref)
+                    .map_or(trait_ref, |normalized| normalized.value);
                 (similarity, normalized)
             })
             .collect::<Vec<_>>();
@@ -2032,15 +2077,10 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         param_env: ty::ParamEnv<'tcx>,
         trait_ref_and_ty: ty::Binder<'tcx, (ty::TraitPredicate<'tcx>, Ty<'tcx>)>,
     ) -> PredicateObligation<'tcx> {
-        let trait_pred = trait_ref_and_ty.map_bound_ref(|(tr, new_self_ty)| ty::TraitPredicate {
-            trait_ref: ty::TraitRef {
-                substs: self.tcx.mk_substs_trait(*new_self_ty, &tr.trait_ref.substs[1..]),
-                ..tr.trait_ref
-            },
-            ..*tr
-        });
+        let trait_pred = trait_ref_and_ty
+            .map_bound(|(tr, new_self_ty)| tr.with_self_type(self.tcx, new_self_ty));
 
-        Obligation::new(ObligationCause::dummy(), param_env, trait_pred.to_predicate(self.tcx))
+        Obligation::new(self.tcx, ObligationCause::dummy(), param_env, trait_pred)
     }
 
     #[instrument(skip(self), level = "debug")]
@@ -2064,7 +2104,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
 
         let bound_predicate = predicate.kind();
         let mut err = match bound_predicate.skip_binder() {
-            ty::PredicateKind::Trait(data) => {
+            ty::PredicateKind::Clause(ty::Clause::Trait(data)) => {
                 let trait_ref = bound_predicate.rebind(data.trait_ref);
                 debug!(?trait_ref);
 
@@ -2088,7 +2128,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 // check upstream for type errors and don't add the obligations to
                 // begin with in those cases.
                 if self.tcx.lang_items().sized_trait() == Some(trait_ref.def_id()) {
-                    if !self.is_tainted_by_errors() {
+                    if let None = self.tainted_by_errors() {
                         self.emit_inference_failure_err(
                             body_id,
                             span,
@@ -2128,21 +2168,27 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                     )
                 };
 
-                let obligation = Obligation::new(
-                    obligation.cause.clone(),
-                    obligation.param_env,
-                    trait_ref.to_poly_trait_predicate(),
-                );
-                let mut selcx = SelectionContext::with_query_mode(
-                    &self,
-                    crate::traits::TraitQueryMode::Standard,
-                );
+                let obligation = obligation.with(self.tcx, trait_ref);
+                let mut selcx = SelectionContext::new(&self);
                 match selcx.select_from_obligation(&obligation) {
-                    Err(SelectionError::Ambiguous(impls)) if impls.len() > 1 => {
-                        self.annotate_source_of_ambiguity(&mut err, &impls, predicate);
+                    Ok(None) => {
+                        let impls = ambiguity::recompute_applicable_impls(self.infcx, &obligation);
+                        let has_non_region_infer =
+                            trait_ref.skip_binder().substs.types().any(|t| !t.is_ty_infer());
+                        // It doesn't make sense to talk about applicable impls if there are more
+                        // than a handful of them.
+                        if impls.len() > 1 && impls.len() < 5 && has_non_region_infer {
+                            self.annotate_source_of_ambiguity(&mut err, &impls, predicate);
+                        } else {
+                            if self.tainted_by_errors().is_some() {
+                                err.cancel();
+                                return;
+                            }
+                            err.note(&format!("cannot satisfy `{}`", predicate));
+                        }
                     }
                     _ => {
-                        if self.is_tainted_by_errors() {
+                        if self.tainted_by_errors().is_some() {
                             err.cancel();
                             return;
                         }
@@ -2160,7 +2206,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                     if generics.params.iter().any(|p| p.name != kw::SelfUpper)
                         && !snippet.ends_with('>')
                         && !generics.has_impl_trait()
-                        && !self.tcx.fn_trait_kind_from_lang_item(def_id).is_some()
+                        && !self.tcx.is_fn_trait(def_id)
                     {
                         // FIXME: To avoid spurious suggestions in functions where type arguments
                         // where already supplied, we check the snippet to make sure it doesn't
@@ -2245,7 +2291,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                         ] = path.segments
                         && data.trait_ref.def_id == *trait_id
                         && self.tcx.trait_of_item(*item_id) == Some(*trait_id)
-                        && !self.is_tainted_by_errors()
+                        && let None = self.tainted_by_errors()
                     {
                         let (verb, noun) = match self.tcx.associated_item(item_id).kind {
                             ty::AssocKind::Const => ("refer to the", "constant"),
@@ -2314,7 +2360,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 // with error messages.
                 if arg.references_error()
                     || self.tcx.sess.has_errors().is_some()
-                    || self.is_tainted_by_errors()
+                    || self.tainted_by_errors().is_some()
                 {
                     return;
                 }
@@ -2325,7 +2371,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             ty::PredicateKind::Subtype(data) => {
                 if data.references_error()
                     || self.tcx.sess.has_errors().is_some()
-                    || self.is_tainted_by_errors()
+                    || self.tainted_by_errors().is_some()
                 {
                     // no need to overload user in such cases
                     return;
@@ -2335,8 +2381,8 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 assert!(a.is_ty_var() && b.is_ty_var());
                 self.emit_inference_failure_err(body_id, span, a.into(), ErrorCode::E0282, true)
             }
-            ty::PredicateKind::Projection(data) => {
-                if predicate.references_error() || self.is_tainted_by_errors() {
+            ty::PredicateKind::Clause(ty::Clause::Projection(data)) => {
+                if predicate.references_error() || self.tainted_by_errors().is_some() {
                     return;
                 }
                 let subst = data
@@ -2370,7 +2416,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             }
 
             ty::PredicateKind::ConstEvaluatable(data) => {
-                if predicate.references_error() || self.is_tainted_by_errors() {
+                if predicate.references_error() || self.tainted_by_errors().is_some() {
                     return;
                 }
                 let subst = data.walk().find(|g| g.is_non_region_infer());
@@ -2397,7 +2443,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 }
             }
             _ => {
-                if self.tcx.sess.has_errors().is_some() || self.is_tainted_by_errors() {
+                if self.tcx.sess.has_errors().is_some() || self.tainted_by_errors().is_some() {
                     return;
                 }
                 let mut err = struct_span_err!(
@@ -2435,14 +2481,13 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 }
             }
         }
-        let msg = format!("multiple `impl`s satisfying `{}` found", predicate);
         let mut crate_names: Vec<_> = crates.iter().map(|n| format!("`{}`", n)).collect();
         crate_names.sort();
         crate_names.dedup();
         post.sort();
         post.dedup();
 
-        if self.is_tainted_by_errors()
+        if self.tainted_by_errors().is_some()
             && (crate_names.len() == 1
                 && spans.len() == 0
                 && ["`core`", "`alloc`", "`std`"].contains(&crate_names[0].as_str())
@@ -2456,13 +2501,9 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             err.downgrade_to_delayed_bug();
             return;
         }
-        let post = if post.len() > 4 {
-            format!(
-                ":\n{}\nand {} more",
-                post.iter().map(|p| format!("- {}", p)).take(4).collect::<Vec<_>>().join("\n"),
-                post.len() - 4,
-            )
-        } else if post.len() > 1 || (post.len() == 1 && post[0].contains('\n')) {
+
+        let msg = format!("multiple `impl`s satisfying `{}` found", predicate);
+        let post = if post.len() > 1 || (post.len() == 1 && post[0].contains('\n')) {
             format!(":\n{}", post.iter().map(|p| format!("- {}", p)).collect::<Vec<_>>().join("\n"),)
         } else if post.len() == 1 {
             format!(": `{}`", post[0])
@@ -2541,24 +2582,14 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         }
 
         self.probe(|_| {
-            let mut selcx = SelectionContext::new(self);
-
             let cleaned_pred =
                 pred.fold_with(&mut ParamToVarFolder { infcx: self, var_map: Default::default() });
 
-            let cleaned_pred = super::project::normalize(
-                &mut selcx,
-                param_env,
-                ObligationCause::dummy(),
-                cleaned_pred,
-            )
-            .value;
-
-            let obligation = Obligation::new(
-                ObligationCause::dummy(),
-                param_env,
-                cleaned_pred.to_predicate(selcx.tcx()),
-            );
+            let InferOk { value: cleaned_pred, .. } =
+                self.infcx.at(&ObligationCause::dummy(), param_env).normalize(cleaned_pred);
+
+            let obligation =
+                Obligation::new(self.tcx, ObligationCause::dummy(), param_env, cleaned_pred);
 
             self.predicate_may_hold(&obligation)
         })
@@ -2586,7 +2617,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         err: &mut Diagnostic,
         obligation: &PredicateObligation<'tcx>,
     ) {
-        let ty::PredicateKind::Trait(pred) = obligation.predicate.kind().skip_binder() else { return; };
+        let ty::PredicateKind::Clause(ty::Clause::Trait(pred)) = obligation.predicate.kind().skip_binder() else { return; };
         let (ObligationCauseCode::BindingObligation(item_def_id, span)
         | ObligationCauseCode::ExprBindingObligation(item_def_id, span, ..))
             = *obligation.cause.code().peel_derives() else { return; };
@@ -2612,11 +2643,10 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         let Some(param) = generics.params.iter().find(|param| param.span == span) else {
             return;
         };
-        let param_def_id = self.tcx.hir().local_def_id(param.hir_id);
         // Check that none of the explicit trait bounds is `Sized`. Assume that an explicit
         // `Sized` bound is there intentionally and we don't need to suggest relaxing it.
         let explicitly_sized = generics
-            .bounds_for_param(param_def_id)
+            .bounds_for_param(param.def_id)
             .flat_map(|bp| bp.bounds)
             .any(|bound| bound.trait_ref().and_then(|tr| tr.trait_def_id()) == sized_trait);
         if explicitly_sized {
@@ -2639,7 +2669,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             _ => {}
         };
         // Didn't add an indirection suggestion, so add a general suggestion to relax `Sized`.
-        let (span, separator) = if let Some(s) = generics.bounds_span_for_suggestions(param_def_id)
+        let (span, separator) = if let Some(s) = generics.bounds_span_for_suggestions(param.def_id)
         {
             (s, " +")
         } else {
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs
index 5eef54c63..9bfe52764 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs
@@ -1,14 +1,22 @@
-use super::{
-    ObligationCauseCode, OnUnimplementedDirective, OnUnimplementedNote, PredicateObligation,
-};
+use super::{ObligationCauseCode, PredicateObligation};
 use crate::infer::error_reporting::TypeErrCtxt;
+use rustc_ast::{MetaItem, NestedMetaItem};
+use rustc_attr as attr;
+use rustc_data_structures::fx::FxHashMap;
+use rustc_errors::{struct_span_err, ErrorGuaranteed};
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
 use rustc_middle::ty::SubstsRef;
-use rustc_middle::ty::{self, GenericParamDefKind};
-use rustc_span::symbol::sym;
+use rustc_middle::ty::{self, GenericParamDefKind, TyCtxt};
+use rustc_parse_format::{ParseMode, Parser, Piece, Position};
+use rustc_span::symbol::{kw, sym, Symbol};
+use rustc_span::{Span, DUMMY_SP};
 use std::iter;
 
+use crate::errors::{
+    EmptyOnClauseInOnUnimplemented, InvalidOnClauseInOnUnimplemented, NoValueInOnUnimplemented,
+};
+
 use super::InferCtxtPrivExt;
 
 pub trait TypeErrCtxtExt<'tcx> {
@@ -276,3 +284,383 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         }
     }
 }
+
+#[derive(Clone, Debug)]
+pub struct OnUnimplementedFormatString(Symbol);
+
+#[derive(Debug)]
+pub struct OnUnimplementedDirective {
+    pub condition: Option<MetaItem>,
+    pub subcommands: Vec<OnUnimplementedDirective>,
+    pub message: Option<OnUnimplementedFormatString>,
+    pub label: Option<OnUnimplementedFormatString>,
+    pub note: Option<OnUnimplementedFormatString>,
+    pub parent_label: Option<OnUnimplementedFormatString>,
+    pub append_const_msg: Option<Option<Symbol>>,
+}
+
+/// For the `#[rustc_on_unimplemented]` attribute
+#[derive(Default)]
+pub struct OnUnimplementedNote {
+    pub message: Option<String>,
+    pub label: Option<String>,
+    pub note: Option<String>,
+    pub parent_label: Option<String>,
+    /// Append a message for `~const Trait` errors. `None` means not requested and
+    /// should fallback to a generic message, `Some(None)` suggests using the default
+    /// appended message, `Some(Some(s))` suggests use the `s` message instead of the
+    /// default one..
+    pub append_const_msg: Option<Option<Symbol>>,
+}
+
+impl<'tcx> OnUnimplementedDirective {
+    fn parse(
+        tcx: TyCtxt<'tcx>,
+        item_def_id: DefId,
+        items: &[NestedMetaItem],
+        span: Span,
+        is_root: bool,
+    ) -> Result<Self, ErrorGuaranteed> {
+        let mut errored = None;
+        let mut item_iter = items.iter();
+
+        let parse_value = |value_str| {
+            OnUnimplementedFormatString::try_parse(tcx, item_def_id, value_str, span).map(Some)
+        };
+
+        let condition = if is_root {
+            None
+        } else {
+            let cond = item_iter
+                .next()
+                .ok_or_else(|| tcx.sess.emit_err(EmptyOnClauseInOnUnimplemented { span }))?
+                .meta_item()
+                .ok_or_else(|| tcx.sess.emit_err(InvalidOnClauseInOnUnimplemented { span }))?;
+            attr::eval_condition(cond, &tcx.sess.parse_sess, Some(tcx.features()), &mut |cfg| {
+                if let Some(value) = cfg.value && let Err(guar) = parse_value(value) {
+                    errored = Some(guar);
+                }
+                true
+            });
+            Some(cond.clone())
+        };
+
+        let mut message = None;
+        let mut label = None;
+        let mut note = None;
+        let mut parent_label = None;
+        let mut subcommands = vec![];
+        let mut append_const_msg = None;
+
+        for item in item_iter {
+            if item.has_name(sym::message) && message.is_none() {
+                if let Some(message_) = item.value_str() {
+                    message = parse_value(message_)?;
+                    continue;
+                }
+            } else if item.has_name(sym::label) && label.is_none() {
+                if let Some(label_) = item.value_str() {
+                    label = parse_value(label_)?;
+                    continue;
+                }
+            } else if item.has_name(sym::note) && note.is_none() {
+                if let Some(note_) = item.value_str() {
+                    note = parse_value(note_)?;
+                    continue;
+                }
+            } else if item.has_name(sym::parent_label) && parent_label.is_none() {
+                if let Some(parent_label_) = item.value_str() {
+                    parent_label = parse_value(parent_label_)?;
+                    continue;
+                }
+            } else if item.has_name(sym::on)
+                && is_root
+                && message.is_none()
+                && label.is_none()
+                && note.is_none()
+            {
+                if let Some(items) = item.meta_item_list() {
+                    match Self::parse(tcx, item_def_id, &items, item.span(), false) {
+                        Ok(subcommand) => subcommands.push(subcommand),
+                        Err(reported) => errored = Some(reported),
+                    };
+                    continue;
+                }
+            } else if item.has_name(sym::append_const_msg) && append_const_msg.is_none() {
+                if let Some(msg) = item.value_str() {
+                    append_const_msg = Some(Some(msg));
+                    continue;
+                } else if item.is_word() {
+                    append_const_msg = Some(None);
+                    continue;
+                }
+            }
+
+            // nothing found
+            tcx.sess.emit_err(NoValueInOnUnimplemented { span: item.span() });
+        }
+
+        if let Some(reported) = errored {
+            Err(reported)
+        } else {
+            Ok(OnUnimplementedDirective {
+                condition,
+                subcommands,
+                message,
+                label,
+                note,
+                parent_label,
+                append_const_msg,
+            })
+        }
+    }
+
+    pub fn of_item(tcx: TyCtxt<'tcx>, item_def_id: DefId) -> Result<Option<Self>, ErrorGuaranteed> {
+        let Some(attr) = tcx.get_attr(item_def_id, sym::rustc_on_unimplemented) else {
+            return Ok(None);
+        };
+
+        let result = if let Some(items) = attr.meta_item_list() {
+            Self::parse(tcx, item_def_id, &items, attr.span, true).map(Some)
+        } else if let Some(value) = attr.value_str() {
+            Ok(Some(OnUnimplementedDirective {
+                condition: None,
+                message: None,
+                subcommands: vec![],
+                label: Some(OnUnimplementedFormatString::try_parse(
+                    tcx,
+                    item_def_id,
+                    value,
+                    attr.span,
+                )?),
+                note: None,
+                parent_label: None,
+                append_const_msg: None,
+            }))
+        } else {
+            let reported =
+                tcx.sess.delay_span_bug(DUMMY_SP, "of_item: neither meta_item_list nor value_str");
+            return Err(reported);
+        };
+        debug!("of_item({:?}) = {:?}", item_def_id, result);
+        result
+    }
+
+    pub fn evaluate(
+        &self,
+        tcx: TyCtxt<'tcx>,
+        trait_ref: ty::TraitRef<'tcx>,
+        options: &[(Symbol, Option<String>)],
+    ) -> OnUnimplementedNote {
+        let mut message = None;
+        let mut label = None;
+        let mut note = None;
+        let mut parent_label = None;
+        let mut append_const_msg = None;
+        info!("evaluate({:?}, trait_ref={:?}, options={:?})", self, trait_ref, options);
+
+        let options_map: FxHashMap<Symbol, String> =
+            options.iter().filter_map(|(k, v)| v.clone().map(|v| (*k, v))).collect();
+
+        for command in self.subcommands.iter().chain(Some(self)).rev() {
+            if let Some(ref condition) = command.condition && !attr::eval_condition(
+                condition,
+                &tcx.sess.parse_sess,
+                Some(tcx.features()),
+                &mut |cfg| {
+                    let value = cfg.value.map(|v| {
+                        OnUnimplementedFormatString(v).format(tcx, trait_ref, &options_map)
+                    });
+
+                    options.contains(&(cfg.name, value))
+                },
+            ) {
+                debug!("evaluate: skipping {:?} due to condition", command);
+                continue;
+            }
+            debug!("evaluate: {:?} succeeded", command);
+            if let Some(ref message_) = command.message {
+                message = Some(message_.clone());
+            }
+
+            if let Some(ref label_) = command.label {
+                label = Some(label_.clone());
+            }
+
+            if let Some(ref note_) = command.note {
+                note = Some(note_.clone());
+            }
+
+            if let Some(ref parent_label_) = command.parent_label {
+                parent_label = Some(parent_label_.clone());
+            }
+
+            append_const_msg = command.append_const_msg;
+        }
+
+        OnUnimplementedNote {
+            label: label.map(|l| l.format(tcx, trait_ref, &options_map)),
+            message: message.map(|m| m.format(tcx, trait_ref, &options_map)),
+            note: note.map(|n| n.format(tcx, trait_ref, &options_map)),
+            parent_label: parent_label.map(|e_s| e_s.format(tcx, trait_ref, &options_map)),
+            append_const_msg,
+        }
+    }
+}
+
+impl<'tcx> OnUnimplementedFormatString {
+    fn try_parse(
+        tcx: TyCtxt<'tcx>,
+        item_def_id: DefId,
+        from: Symbol,
+        err_sp: Span,
+    ) -> Result<Self, ErrorGuaranteed> {
+        let result = OnUnimplementedFormatString(from);
+        result.verify(tcx, item_def_id, err_sp)?;
+        Ok(result)
+    }
+
+    fn verify(
+        &self,
+        tcx: TyCtxt<'tcx>,
+        item_def_id: DefId,
+        span: Span,
+    ) -> Result<(), ErrorGuaranteed> {
+        let trait_def_id = if tcx.is_trait(item_def_id) {
+            item_def_id
+        } else {
+            tcx.trait_id_of_impl(item_def_id)
+                .expect("expected `on_unimplemented` to correspond to a trait")
+        };
+        let trait_name = tcx.item_name(trait_def_id);
+        let generics = tcx.generics_of(item_def_id);
+        let s = self.0.as_str();
+        let parser = Parser::new(s, None, None, false, ParseMode::Format);
+        let mut result = Ok(());
+        for token in parser {
+            match token {
+                Piece::String(_) => (), // Normal string, no need to check it
+                Piece::NextArgument(a) => match a.position {
+                    Position::ArgumentNamed(s) => {
+                        match Symbol::intern(s) {
+                            // `{Self}` is allowed
+                            kw::SelfUpper => (),
+                            // `{ThisTraitsName}` is allowed
+                            s if s == trait_name => (),
+                            // `{from_method}` is allowed
+                            sym::from_method => (),
+                            // `{from_desugaring}` is allowed
+                            sym::from_desugaring => (),
+                            // `{ItemContext}` is allowed
+                            sym::ItemContext => (),
+                            // `{integral}` and `{integer}` and `{float}` are allowed
+                            sym::integral | sym::integer_ | sym::float => (),
+                            // So is `{A}` if A is a type parameter
+                            s => match generics.params.iter().find(|param| param.name == s) {
+                                Some(_) => (),
+                                None => {
+                                    let reported = struct_span_err!(
+                                        tcx.sess,
+                                        span,
+                                        E0230,
+                                        "there is no parameter `{}` on {}",
+                                        s,
+                                        if trait_def_id == item_def_id {
+                                            format!("trait `{}`", trait_name)
+                                        } else {
+                                            "impl".to_string()
+                                        }
+                                    )
+                                    .emit();
+                                    result = Err(reported);
+                                }
+                            },
+                        }
+                    }
+                    // `{:1}` and `{}` are not to be used
+                    Position::ArgumentIs(..) | Position::ArgumentImplicitlyIs(_) => {
+                        let reported = struct_span_err!(
+                            tcx.sess,
+                            span,
+                            E0231,
+                            "only named substitution parameters are allowed"
+                        )
+                        .emit();
+                        result = Err(reported);
+                    }
+                },
+            }
+        }
+
+        result
+    }
+
+    pub fn format(
+        &self,
+        tcx: TyCtxt<'tcx>,
+        trait_ref: ty::TraitRef<'tcx>,
+        options: &FxHashMap<Symbol, String>,
+    ) -> String {
+        let name = tcx.item_name(trait_ref.def_id);
+        let trait_str = tcx.def_path_str(trait_ref.def_id);
+        let generics = tcx.generics_of(trait_ref.def_id);
+        let generic_map = generics
+            .params
+            .iter()
+            .filter_map(|param| {
+                let value = match param.kind {
+                    GenericParamDefKind::Type { .. } | GenericParamDefKind::Const { .. } => {
+                        trait_ref.substs[param.index as usize].to_string()
+                    }
+                    GenericParamDefKind::Lifetime => return None,
+                };
+                let name = param.name;
+                Some((name, value))
+            })
+            .collect::<FxHashMap<Symbol, String>>();
+        let empty_string = String::new();
+
+        let s = self.0.as_str();
+        let parser = Parser::new(s, None, None, false, ParseMode::Format);
+        let item_context = (options.get(&sym::ItemContext)).unwrap_or(&empty_string);
+        parser
+            .map(|p| match p {
+                Piece::String(s) => s,
+                Piece::NextArgument(a) => match a.position {
+                    Position::ArgumentNamed(s) => {
+                        let s = Symbol::intern(s);
+                        match generic_map.get(&s) {
+                            Some(val) => val,
+                            None if s == name => &trait_str,
+                            None => {
+                                if let Some(val) = options.get(&s) {
+                                    val
+                                } else if s == sym::from_desugaring || s == sym::from_method {
+                                    // don't break messages using these two arguments incorrectly
+                                    &empty_string
+                                } else if s == sym::ItemContext {
+                                    &item_context
+                                } else if s == sym::integral {
+                                    "{integral}"
+                                } else if s == sym::integer_ {
+                                    "{integer}"
+                                } else if s == sym::float {
+                                    "{float}"
+                                } else {
+                                    bug!(
+                                        "broken on_unimplemented {:?} for {:?}: \
+                                      no argument matching {:?}",
+                                        self.0,
+                                        trait_ref,
+                                        s
+                                    )
+                                }
+                            }
+                        }
+                    }
+                    _ => bug!("broken on_unimplemented {:?} - bad format arg", self.0),
+                },
+            })
+            .collect()
+    }
+}
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
index 8c41d9d24..6ea54b625 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
@@ -1,11 +1,8 @@
-use super::{
-    DefIdOrName, Obligation, ObligationCause, ObligationCauseCode, PredicateObligation,
-    SelectionContext,
-};
+use super::{DefIdOrName, Obligation, ObligationCause, ObligationCauseCode, PredicateObligation};
 
 use crate::autoderef::Autoderef;
 use crate::infer::InferCtxt;
-use crate::traits::normalize_to;
+use crate::traits::NormalizeExt;
 
 use hir::def::CtorOf;
 use hir::HirId;
@@ -23,7 +20,7 @@ use rustc_hir::lang_items::LangItem;
 use rustc_hir::{AsyncGeneratorKind, GeneratorKind, Node};
 use rustc_infer::infer::error_reporting::TypeErrCtxt;
 use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
-use rustc_infer::infer::LateBoundRegionConversionTime;
+use rustc_infer::infer::{InferOk, LateBoundRegionConversionTime};
 use rustc_middle::hir::map;
 use rustc_middle::ty::{
     self, suggest_arbitrary_trait_bound, suggest_constraining_type_param, AdtKind, DefIdTree,
@@ -44,7 +41,7 @@ use rustc_middle::ty::print::with_no_trimmed_paths;
 #[derive(Debug)]
 pub enum GeneratorInteriorOrUpvar {
     // span of interior type
-    Interior(Span),
+    Interior(Span, Option<(Option<Span>, Span, Option<hir::HirId>, Option<Span>)>),
     // span of upvar
     Upvar(Span),
 }
@@ -283,7 +280,6 @@ pub trait TypeErrCtxtExt<'tcx> {
         &self,
         err: &mut Diagnostic,
         interior_or_upvar_span: GeneratorInteriorOrUpvar,
-        interior_extra_info: Option<(Option<Span>, Span, Option<hir::HirId>, Option<Span>)>,
         is_async: bool,
         outer_generator: Option<DefId>,
         trait_pred: ty::TraitPredicate<'tcx>,
@@ -302,7 +298,7 @@ pub trait TypeErrCtxtExt<'tcx> {
         obligated_types: &mut Vec<Ty<'tcx>>,
         seen_requirements: &mut FxHashSet<DefId>,
     ) where
-        T: fmt::Display;
+        T: fmt::Display + ToPredicate<'tcx>;
 
     /// Suggest to await before try: future? => future.await?
     fn suggest_await_before_try(
@@ -335,7 +331,7 @@ pub trait TypeErrCtxtExt<'tcx> {
     );
 }
 
-fn predicate_constraint(generics: &hir::Generics<'_>, pred: String) -> (Span, String) {
+fn predicate_constraint(generics: &hir::Generics<'_>, pred: ty::Predicate<'_>) -> (Span, String) {
     (
         generics.tail_span_for_predicate_suggestion(),
         format!("{} {}", generics.add_where_or_trailing_comma(), pred),
@@ -417,7 +413,7 @@ fn suggest_restriction<'tcx>(
             },
             // `fn foo(t: impl Trait)`
             //                       ^ suggest `where <T as Trait>::A: Bound`
-            predicate_constraint(hir_generics, trait_pred.to_predicate(tcx).to_string()),
+            predicate_constraint(hir_generics, trait_pred.to_predicate(tcx)),
         ];
         sugg.extend(ty_spans.into_iter().map(|s| (s, type_param_name.to_string())));
 
@@ -441,9 +437,7 @@ fn suggest_restriction<'tcx>(
                 .find(|p| !matches!(p.kind, hir::GenericParamKind::Type { synthetic: true, .. })),
             super_traits,
         ) {
-            (_, None) => {
-                predicate_constraint(hir_generics, trait_pred.to_predicate(tcx).to_string())
-            }
+            (_, None) => predicate_constraint(hir_generics, trait_pred.to_predicate(tcx)),
             (None, Some((ident, []))) => (
                 ident.span.shrink_to_hi(),
                 format!(": {}", trait_pred.print_modifiers_and_trait_path()),
@@ -714,7 +708,6 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                     obligation.cause.body_id,
                     span,
                     base_ty,
-                    span,
                 );
                 if let Some(steps) = autoderef.find_map(|(ty, steps)| {
                     // Re-add the `&`
@@ -814,7 +807,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         err: &mut Diagnostic,
         trait_pred: ty::PolyTraitPredicate<'tcx>,
     ) -> bool {
-        if let ty::PredicateKind::Trait(trait_pred) = obligation.predicate.kind().skip_binder()
+        if let ty::PredicateKind::Clause(ty::Clause::Trait(trait_pred)) = obligation.predicate.kind().skip_binder()
             && Some(trait_pred.def_id()) == self.tcx.lang_items().sized_trait()
         {
             // Don't suggest calling to turn an unsized type into a sized type
@@ -843,7 +836,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             }
             ty::Opaque(def_id, substs) => {
                 self.tcx.bound_item_bounds(def_id).subst(self.tcx, substs).iter().find_map(|pred| {
-                    if let ty::PredicateKind::Projection(proj) = pred.kind().skip_binder()
+                    if let ty::PredicateKind::Clause(ty::Clause::Projection(proj)) = pred.kind().skip_binder()
                     && Some(proj.projection_ty.item_def_id) == self.tcx.lang_items().fn_once_output()
                     // args tuple will always be substs[1]
                     && let ty::Tuple(args) = proj.projection_ty.substs.type_at(1).kind()
@@ -877,7 +870,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             }
             ty::Param(_) => {
                 obligation.param_env.caller_bounds().iter().find_map(|pred| {
-                    if let ty::PredicateKind::Projection(proj) = pred.kind().skip_binder()
+                    if let ty::PredicateKind::Clause(ty::Clause::Projection(proj)) = pred.kind().skip_binder()
                     && Some(proj.projection_ty.item_def_id) == self.tcx.lang_items().fn_once_output()
                     && proj.projection_ty.self_ty() == found
                     // args tuple will always be substs[1]
@@ -1019,7 +1012,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         let mut never_suggest_borrow: Vec<_> =
             [LangItem::Copy, LangItem::Clone, LangItem::Unpin, LangItem::Sized]
                 .iter()
-                .filter_map(|lang_item| self.tcx.lang_items().require(*lang_item).ok())
+                .filter_map(|lang_item| self.tcx.lang_items().get(*lang_item))
                 .collect();
 
         if let Some(def_id) = self.tcx.get_diagnostic_item(sym::Send) {
@@ -1063,7 +1056,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 {
                     (
                         mk_result(old_pred.map_bound(|trait_pred| (trait_pred, *ty))),
-                        matches!(mutability, hir::Mutability::Mut),
+                        mutability.is_mut(),
                     )
                 } else {
                     (false, false)
@@ -1117,7 +1110,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                         err.span_suggestions(
                             span.shrink_to_lo(),
                             "consider borrowing here",
-                            ["&".to_string(), "&mut ".to_string()].into_iter(),
+                            ["&".to_string(), "&mut ".to_string()],
                             Applicability::MaybeIncorrect,
                         );
                     } else {
@@ -1164,7 +1157,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
 
         for predicate in predicates.iter() {
             if !self.predicate_must_hold_modulo_regions(
-                &obligation.with(predicate.with_self_ty(self.tcx, self_ref_ty)),
+                &obligation.with(self.tcx, predicate.with_self_ty(self.tcx, self_ref_ty)),
             ) {
                 return;
             }
@@ -1260,7 +1253,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                     );
                     // FIXME: account for associated `async fn`s.
                     if let hir::Expr { span, kind: hir::ExprKind::Call(base, _), .. } = expr {
-                        if let ty::PredicateKind::Trait(pred) =
+                        if let ty::PredicateKind::Clause(ty::Clause::Trait(pred)) =
                             obligation.predicate.kind().skip_binder()
                         {
                             err.span_label(
@@ -1353,7 +1346,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                         .sess
                         .source_map()
                         .span_take_while(span, |c| c.is_whitespace() || *c == '&');
-                    if points_at_arg && mutability == hir::Mutability::Not && refs_number > 0 {
+                    if points_at_arg && mutability.is_not() && refs_number > 0 {
                         err.span_suggestion_verbose(
                             sp,
                             "consider changing this borrow's mutability",
@@ -1525,7 +1518,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                         let self_ty_satisfies_dyn_predicates = |self_ty| {
                             predicates.iter().all(|predicate| {
                                 let pred = predicate.with_self_ty(self.tcx, self_ty);
-                                let obl = Obligation::new(cause.clone(), param_env, pred);
+                                let obl = Obligation::new(self.tcx, cause.clone(), param_env, pred);
                                 self.predicate_may_hold(&obl)
                             })
                         };
@@ -1688,9 +1681,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         ) -> Ty<'tcx> {
             let inputs = trait_ref.skip_binder().substs.type_at(1);
             let sig = match inputs.kind() {
-                ty::Tuple(inputs)
-                    if infcx.tcx.fn_trait_kind_from_lang_item(trait_ref.def_id()).is_some() =>
-                {
+                ty::Tuple(inputs) if infcx.tcx.is_fn_trait(trait_ref.def_id()) => {
                     infcx.tcx.mk_fn_sig(
                         inputs.iter(),
                         infcx.next_ty_var(TypeVariableOrigin {
@@ -1760,8 +1751,8 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         if let ObligationCauseCode::ExprBindingObligation(def_id, _, _, idx) = cause
             && let predicates = self.tcx.predicates_of(def_id).instantiate_identity(self.tcx)
             && let Some(pred) = predicates.predicates.get(*idx)
-            && let ty::PredicateKind::Trait(trait_pred) = pred.kind().skip_binder()
-            && ty::ClosureKind::from_def_id(self.tcx, trait_pred.def_id()).is_some()
+            && let ty::PredicateKind::Clause(ty::Clause::Trait(trait_pred)) = pred.kind().skip_binder()
+            && self.tcx.is_fn_trait(trait_pred.def_id())
         {
             let expected_self =
                 self.tcx.anonymize_late_bound_regions(pred.kind().rebind(trait_pred.self_ty()));
@@ -1774,9 +1765,8 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             let other_pred = std::iter::zip(&predicates.predicates, &predicates.spans)
                 .enumerate()
                 .find(|(other_idx, (pred, _))| match pred.kind().skip_binder() {
-                    ty::PredicateKind::Trait(trait_pred)
-                        if ty::ClosureKind::from_def_id(self.tcx, trait_pred.def_id())
-                            .is_some()
+                    ty::PredicateKind::Clause(ty::Clause::Trait(trait_pred))
+                        if self.tcx.is_fn_trait(trait_pred.def_id())
                             && other_idx != idx
                             // Make sure that the self type matches
                             // (i.e. constraining this closure)
@@ -1890,13 +1880,9 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         //
         // - `BuiltinDerivedObligation` with a generator witness (B)
         // - `BuiltinDerivedObligation` with a generator (B)
-        // - `BuiltinDerivedObligation` with `std::future::GenFuture` (B)
-        // - `BuiltinDerivedObligation` with `impl std::future::Future` (B)
         // - `BuiltinDerivedObligation` with `impl std::future::Future` (B)
         // - `BuiltinDerivedObligation` with a generator witness (A)
         // - `BuiltinDerivedObligation` with a generator (A)
-        // - `BuiltinDerivedObligation` with `std::future::GenFuture` (A)
-        // - `BuiltinDerivedObligation` with `impl std::future::Future` (A)
         // - `BuiltinDerivedObligation` with `impl std::future::Future` (A)
         // - `BindingObligation` with `impl_send (Send requirement)
         //
@@ -1905,7 +1891,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         // bound was introduced. At least one generator should be present for this diagnostic to be
         // modified.
         let (mut trait_ref, mut target_ty) = match obligation.predicate.kind().skip_binder() {
-            ty::PredicateKind::Trait(p) => (Some(p), Some(p.self_ty())),
+            ty::PredicateKind::Clause(ty::Clause::Trait(p)) => (Some(p), Some(p.self_ty())),
             _ => (None, None),
         };
         let mut generator = None;
@@ -2004,17 +1990,6 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             .as_local()
             .and_then(|def_id| hir.maybe_body_owned_by(def_id))
             .map(|body_id| hir.body(body_id));
-        let is_async = match generator_did.as_local() {
-            Some(_) => generator_body
-                .and_then(|body| body.generator_kind())
-                .map(|generator_kind| matches!(generator_kind, hir::GeneratorKind::Async(..)))
-                .unwrap_or(false),
-            None => self
-                .tcx
-                .generator_kind(generator_did)
-                .map(|generator_kind| matches!(generator_kind, hir::GeneratorKind::Async(..)))
-                .unwrap_or(false),
-        };
         let mut visitor = AwaitsVisitor::default();
         if let Some(body) = generator_body {
             visitor.visit_body(body);
@@ -2044,61 +2019,61 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             eq
         };
 
-        let mut interior_or_upvar_span = None;
-        let mut interior_extra_info = None;
-
         // Get the typeck results from the infcx if the generator is the function we are currently
         // type-checking; otherwise, get them by performing a query.  This is needed to avoid
         // cycles. If we can't use resolved types because the generator comes from another crate,
         // we still provide a targeted error but without all the relevant spans.
-        let generator_data: Option<GeneratorData<'tcx, '_>> = match &self.typeck_results {
-            Some(t) if t.hir_owner.to_def_id() == generator_did_root => {
-                Some(GeneratorData::Local(&t))
-            }
+        let generator_data = match &self.typeck_results {
+            Some(t) if t.hir_owner.to_def_id() == generator_did_root => GeneratorData::Local(&t),
             _ if generator_did.is_local() => {
-                Some(GeneratorData::Local(self.tcx.typeck(generator_did.expect_local())))
+                GeneratorData::Local(self.tcx.typeck(generator_did.expect_local()))
             }
-            _ => self
-                .tcx
-                .generator_diagnostic_data(generator_did)
-                .as_ref()
-                .map(|generator_diag_data| GeneratorData::Foreign(generator_diag_data)),
+            _ if let Some(generator_diag_data) = self.tcx.generator_diagnostic_data(generator_did) => {
+                GeneratorData::Foreign(generator_diag_data)
+            }
+            _ => return false,
         };
 
-        if let Some(generator_data) = generator_data.as_ref() {
-            interior_or_upvar_span =
-                generator_data.try_get_upvar_span(&self, generator_did, ty_matches);
+        let mut interior_or_upvar_span = None;
 
-            // The generator interior types share the same binders
-            if let Some(cause) =
-                generator_data.get_generator_interior_types().skip_binder().iter().find(
-                    |ty::GeneratorInteriorTypeCause { ty, .. }| {
-                        ty_matches(generator_data.get_generator_interior_types().rebind(*ty))
-                    },
-                )
-            {
-                let from_awaited_ty = generator_data.get_from_await_ty(visitor, hir, ty_matches);
-                let ty::GeneratorInteriorTypeCause { span, scope_span, yield_span, expr, .. } =
-                    cause;
+        let from_awaited_ty = generator_data.get_from_await_ty(visitor, hir, ty_matches);
+        debug!(?from_awaited_ty);
 
-                interior_or_upvar_span = Some(GeneratorInteriorOrUpvar::Interior(*span));
-                interior_extra_info = Some((*scope_span, *yield_span, *expr, from_awaited_ty));
-            }
+        // The generator interior types share the same binders
+        if let Some(cause) =
+            generator_data.get_generator_interior_types().skip_binder().iter().find(
+                |ty::GeneratorInteriorTypeCause { ty, .. }| {
+                    ty_matches(generator_data.get_generator_interior_types().rebind(*ty))
+                },
+            )
+        {
+            let ty::GeneratorInteriorTypeCause { span, scope_span, yield_span, expr, .. } = cause;
 
-            if interior_or_upvar_span.is_none() && generator_data.is_foreign() {
-                interior_or_upvar_span = Some(GeneratorInteriorOrUpvar::Interior(span));
-            }
+            interior_or_upvar_span = Some(GeneratorInteriorOrUpvar::Interior(
+                *span,
+                Some((*scope_span, *yield_span, *expr, from_awaited_ty)),
+            ));
         }
 
+        if interior_or_upvar_span.is_none() {
+            interior_or_upvar_span =
+                generator_data.try_get_upvar_span(&self, generator_did, ty_matches);
+        }
+
+        if interior_or_upvar_span.is_none() && generator_data.is_foreign() {
+            interior_or_upvar_span = Some(GeneratorInteriorOrUpvar::Interior(span, None));
+        }
+
+        debug!(?interior_or_upvar_span);
         if let Some(interior_or_upvar_span) = interior_or_upvar_span {
-            let typeck_results = generator_data.and_then(|generator_data| match generator_data {
+            let is_async = self.tcx.generator_is_async(generator_did);
+            let typeck_results = match generator_data {
                 GeneratorData::Local(typeck_results) => Some(typeck_results),
                 GeneratorData::Foreign(_) => None,
-            });
+            };
             self.note_obligation_cause_for_async_await(
                 err,
                 interior_or_upvar_span,
-                interior_extra_info,
                 is_async,
                 outer_generator,
                 trait_ref,
@@ -2120,7 +2095,6 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         &self,
         err: &mut Diagnostic,
         interior_or_upvar_span: GeneratorInteriorOrUpvar,
-        interior_extra_info: Option<(Option<Span>, Span, Option<hir::HirId>, Option<Span>)>,
         is_async: bool,
         outer_generator: Option<DefId>,
         trait_pred: ty::TraitPredicate<'tcx>,
@@ -2242,7 +2216,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             }
         };
         match interior_or_upvar_span {
-            GeneratorInteriorOrUpvar::Interior(interior_span) => {
+            GeneratorInteriorOrUpvar::Interior(interior_span, interior_extra_info) => {
                 if let Some((scope_span, yield_span, expr, from_awaited_ty)) = interior_extra_info {
                     if let Some(await_span) = from_awaited_ty {
                         // The type causing this obligation is one being awaited at await_span.
@@ -2379,7 +2353,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         obligated_types: &mut Vec<Ty<'tcx>>,
         seen_requirements: &mut FxHashSet<DefId>,
     ) where
-        T: fmt::Display,
+        T: fmt::Display + ToPredicate<'tcx>,
     {
         let tcx = self.tcx;
         match *cause_code {
@@ -2407,7 +2381,8 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             | ObligationCauseCode::CheckAssociatedTypeBounds { .. }
             | ObligationCauseCode::LetElse
             | ObligationCauseCode::BinOp { .. }
-            | ObligationCauseCode::AscribeUserTypeProvePredicate(..) => {}
+            | ObligationCauseCode::AscribeUserTypeProvePredicate(..)
+            | ObligationCauseCode::RustCall => {}
             ObligationCauseCode::SliceOrArrayElem => {
                 err.note("slice and array elements must have `Sized` type");
             }
@@ -2445,12 +2420,12 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                             (Ok(l), Ok(r)) => l.line == r.line,
                             _ => true,
                         };
-                    if !ident.span.overlaps(span) && !same_line {
+                    if !ident.span.is_dummy() && !ident.span.overlaps(span) && !same_line {
                         multispan.push_span_label(ident.span, "required by a bound in this");
                     }
                 }
                 let descr = format!("required by a bound in `{}`", item_name);
-                if span != DUMMY_SP {
+                if !span.is_dummy() {
                     let msg = format!("required by this bound in `{}`", item_name);
                     multispan.push_span_label(span, msg);
                     err.span_note(multispan, &descr);
@@ -2636,30 +2611,24 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                     }
                 };
 
-                let from_generator = tcx.lang_items().from_generator_fn().unwrap();
+                let identity_future = tcx.require_lang_item(LangItem::IdentityFuture, None);
 
                 // Don't print the tuple of capture types
                 'print: {
                     if !is_upvar_tys_infer_tuple {
                         let msg = format!("required because it appears within the type `{}`", ty);
                         match ty.kind() {
-                            ty::Adt(def, _) => {
-                                // `gen_future` is used in all async functions; it doesn't add any additional info.
-                                if self.tcx.is_diagnostic_item(sym::gen_future, def.did()) {
-                                    break 'print;
-                                }
-                                match self.tcx.opt_item_ident(def.did()) {
-                                    Some(ident) => err.span_note(ident.span, &msg),
-                                    None => err.note(&msg),
-                                }
-                            }
+                            ty::Adt(def, _) => match self.tcx.opt_item_ident(def.did()) {
+                                Some(ident) => err.span_note(ident.span, &msg),
+                                None => err.note(&msg),
+                            },
                             ty::Opaque(def_id, _) => {
-                                // Avoid printing the future from `core::future::from_generator`, it's not helpful
-                                if tcx.parent(*def_id) == from_generator {
+                                // Avoid printing the future from `core::future::identity_future`, it's not helpful
+                                if tcx.parent(*def_id) == identity_future {
                                     break 'print;
                                 }
 
-                                // If the previous type is `from_generator`, this is the future generated by the body of an async function.
+                                // If the previous type is `identity_future`, this is the future generated by the body of an async function.
                                 // Avoid printing it twice (it was already printed in the `ty::Generator` arm below).
                                 let is_future = tcx.ty_is_opaque_future(ty);
                                 debug!(
@@ -2669,8 +2638,8 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                                 );
                                 if is_future
                                     && obligated_types.last().map_or(false, |ty| match ty.kind() {
-                                        ty::Opaque(last_def_id, _) => {
-                                            tcx.parent(*last_def_id) == from_generator
+                                        ty::Generator(last_def_id, ..) => {
+                                            tcx.generator_is_async(*last_def_id)
                                         }
                                         _ => false,
                                     })
@@ -2696,7 +2665,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                                 let sp = self.tcx.def_span(def_id);
 
                                 // Special-case this to say "async block" instead of `[static generator]`.
-                                let kind = tcx.generator_kind(def_id).unwrap();
+                                let kind = tcx.generator_kind(def_id).unwrap().descr();
                                 err.span_note(
                                     sp,
                                     &format!("required because it's used within this {}", kind),
@@ -2713,7 +2682,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
 
                 obligated_types.push(ty);
 
-                let parent_predicate = parent_trait_ref.to_predicate(tcx);
+                let parent_predicate = parent_trait_ref;
                 if !self.is_recursive_obligation(obligated_types, &data.parent_code) {
                     // #74711: avoid a stack overflow
                     ensure_sufficient_stack(|| {
@@ -2744,9 +2713,10 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                     self.resolve_vars_if_possible(data.derived.parent_trait_pred);
                 parent_trait_pred.remap_constness_diag(param_env);
                 let parent_def_id = parent_trait_pred.def_id();
+                let (self_ty, file) =
+                    self.tcx.short_ty_string(parent_trait_pred.skip_binder().self_ty());
                 let msg = format!(
-                    "required for `{}` to implement `{}`",
-                    parent_trait_pred.skip_binder().self_ty(),
+                    "required for `{self_ty}` to implement `{}`",
                     parent_trait_pred.print_modifiers_and_trait_path()
                 );
                 let mut is_auto_trait = false;
@@ -2775,7 +2745,13 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                     _ => err.note(&msg),
                 };
 
-                let mut parent_predicate = parent_trait_pred.to_predicate(tcx);
+                if let Some(file) = file {
+                    err.note(&format!(
+                        "the full type name has been written to '{}'",
+                        file.display(),
+                    ));
+                }
+                let mut parent_predicate = parent_trait_pred;
                 let mut data = &data.derived;
                 let mut count = 0;
                 seen_requirements.insert(parent_def_id);
@@ -2815,11 +2791,18 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                         count,
                         pluralize!(count)
                     ));
+                    let (self_ty, file) =
+                        self.tcx.short_ty_string(parent_trait_pred.skip_binder().self_ty());
                     err.note(&format!(
-                        "required for `{}` to implement `{}`",
-                        parent_trait_pred.skip_binder().self_ty(),
+                        "required for `{self_ty}` to implement `{}`",
                         parent_trait_pred.print_modifiers_and_trait_path()
                     ));
+                    if let Some(file) = file {
+                        err.note(&format!(
+                            "the full type name has been written to '{}'",
+                            file.display(),
+                        ));
+                    }
                 }
                 // #74711: avoid a stack overflow
                 ensure_sufficient_stack(|| {
@@ -2835,7 +2818,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             }
             ObligationCauseCode::DerivedObligation(ref data) => {
                 let parent_trait_ref = self.resolve_vars_if_possible(data.parent_trait_pred);
-                let parent_predicate = parent_trait_ref.to_predicate(tcx);
+                let parent_predicate = parent_trait_ref;
                 // #74711: avoid a stack overflow
                 ensure_sufficient_stack(|| {
                     self.note_obligation_cause_code(
@@ -2968,8 +2951,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 let self_ty = self.resolve_vars_if_possible(trait_pred.self_ty());
                 let impls_future = self.type_implements_trait(
                     future_trait,
-                    self.tcx.erase_late_bound_regions(self_ty),
-                    ty::List::empty(),
+                    [self.tcx.erase_late_bound_regions(self_ty)],
                     obligation.param_env,
                 );
                 if !impls_future.must_apply_modulo_regions() {
@@ -2982,16 +2964,11 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                     self.tcx.mk_projection(
                         item_def_id,
                         // Future::Output has no substs
-                        self.tcx.mk_substs_trait(trait_pred.self_ty(), &[]),
+                        self.tcx.mk_substs_trait(trait_pred.self_ty(), []),
                     )
                 });
-                let projection_ty = normalize_to(
-                    &mut SelectionContext::new(self),
-                    obligation.param_env,
-                    obligation.cause.clone(),
-                    projection_ty,
-                    &mut vec![],
-                );
+                let InferOk { value: projection_ty, .. } =
+                    self.at(&obligation.cause, obligation.param_env).normalize(projection_ty);
 
                 debug!(
                     normalized_projection_type = ?self.resolve_vars_if_possible(projection_ty)
@@ -3067,21 +3044,22 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                     let field_ty = field.ty(self.tcx, substs);
                     let trait_substs = match diagnostic_name {
                         sym::PartialEq | sym::PartialOrd => {
-                            self.tcx.mk_substs_trait(field_ty, &[field_ty.into()])
+                            Some(field_ty)
                         }
-                        _ => self.tcx.mk_substs_trait(field_ty, &[]),
+                        _ => None,
                     };
                     let trait_pred = trait_pred.map_bound_ref(|tr| ty::TraitPredicate {
-                        trait_ref: ty::TraitRef {
-                            substs: trait_substs,
-                            ..trait_pred.skip_binder().trait_ref
-                        },
+                        trait_ref: self.tcx.mk_trait_ref(
+                            trait_pred.def_id(),
+                            [field_ty].into_iter().chain(trait_substs),
+                        ),
                         ..*tr
                     });
                     let field_obl = Obligation::new(
+                        self.tcx,
                         obligation.cause.clone(),
                         obligation.param_env,
-                        trait_pred.to_predicate(self.tcx),
+                        trait_pred,
                     );
                     self.predicate_must_hold_modulo_regions(&field_obl)
                 })